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27 spline interchange?

5K views 7 replies 3 participants last post by  fullsizeaggie 
#1 ·
I am putting a 231 behind a th350 and need a 27 spline input for the 231. Has or does anyone know if there is a 27 spline input from another case that will work? Versus buying a $200 input from Advance?
 
#2 ·
#3 ·
From Advance:

Input gear fits 1995 & Up Jeep NP231 transfer cases. This gear is 5-1/8 O.A.L length and when installed into the transfer case stickouts 2.12

link: 716203A : Jeep NP231 27 Spline long Input Gear | Advance Adapters

S10s and Blazers came with a 231 right? I think my problem with a 231 c input is going to be the width of my adapter plate???
 
#6 ·
Reason I ask is this: a 203/205 version th350 has a very short output shaft stickout (3/4" or so past transmission case), a 208 version has roughly 3" or so.. The 208 version is no where near as common as the 203/205. In order to put a 231 behind it easily, you need the 208 version th350 and then use the stock th350/np208 or 700r4/np208 or np242 adapter.

Now, if you have the short output shaft (203/205), you can use an AA adapter spud shaft that goes from 27 to 23 spline, and then use the 208 or 241 adapter and keep the 23 spline input in the transfer case.
 
#7 ·
Well in my young and dumbness many years ago, (which I might still be slightly plagued with) I bought a th350 to np231 adapter which is mated to my th350. I misplaced the input shaft that came with the kit. I have tried to sell this adapter plate for years with no luck. So without "losing" my money, I am going to go with my original plan. I contemplated all options and decided that this would be most economical, I hope. So now, I am trying to find a 27 spline input that will work in a 231 without having to buy another $200 input from Advance.
 
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